Other humoral factors that have also been associated with hypercalcemia in RCC include IL-6, IL-1, TNFα, transforming growth factor-alpha and beta, and prostaglandins.13,14 IL-6 has been shown to activate osteoclastic bone resorption but it is unclear whether this cytokine causes hypercalcemia directly or by the effect of PTHrP. Here, PTHLH is linked to hypercalcemia disease.